The overall function of the Vector Core is to provide high quality retroviral vectors, including lentiviral vectors, to investigators of this SCOR grant. Many of the projects in this SCOR proposal utilize retroviral vectors as experimental tools to introduce specific genes into hematopoietic cells and other cultured cells. The Vector Core will provide different vector plasmids and packaging cell lines as well as inappropriate technical support relating to the best vectors to use for specific studies. The Vector Core will provide large quantities of vectors required for the baboon studies in Project 6, and will produce these vectors in a dedicated facility under conditions similar to those used for production of vectors for human use. The facilities of the Vector Core can be used by other investigators or Vector Core staff to generate vector-producing cells suitable for human use. Issues of the potential for production of replication-competent viruses will be addressed, and assays for such viruses will be performed for clinical trials and for vectors used in laboratory studies. Safety or toxicity assays that cannot be performed in the Core will be contracted to outside laboratories as needed.